The proof is in Appendix REF . With Lemma REF , a mutual information-based maximum weight spanning tree algorithm, well-known as Chow-Liu algorithm [1]}, could find \(\widehat{\Theta }\)  and identify the multi-phase distribution grid topology. This algorithm has been applied to single-phase system in [2]}. Theorem REF  proves that Chow-Liu algorithm can be extended to multi-phase systems.
